Q.1 Which among the following statements are correct ? 1) Wireless LAN protocols, such as Bluetooth and the IEEE 802.11 specification use microwaves in the 2.4 GHz ISM band 2) (MAN) protocols, such as WiMAX (Worldwide Interoperability for Microwave Access) are based on standards such as IEEE 802.16, designed to operate between 2 to 11 GHz 3) Mobile Broadband Wireless Access (MBWA) protocols operate between 1.6 and 2.3 GHz 4) Mobile phone networks, like GSM, use the low-microwave/high-UHF frequencies around 1.8 and 1.9 GHz Codes: A) 1,3,4 B) 2,3,4 C) 1,2,3 D) 1,2,3,4 Ans. D Q.2 Which among the following statements are correct in context with the LED & LCD ? 1) LCD televisions produce a black and colored image provided by a series of cold cathode fluorescent lamps (CCFLs) 2) LED require more precise current and heat management than compact fluorescent lamp 3) LED have many advantages like lower energy consumption, longer lifetime, improved physical robustness, smaller size Codes: A) 1 & 3 B) 2 & 3 C) 1 & 2 D) 1,2,3 Ans. D LCD Advantages Brightness Produces very bright images due to high peak intensity. Very suitable for environments that are brightly lit . Emissions Produce considerably lower electric, magnetic and electromagnetic fields than CRTs. Geometric Distortion No geometric distortion at the native resolution. Minor distortion can occur for other resolutions. Power Consumption Energy efficient. Consume less than 1/3 the power of a comparable CRT. Consume less electricity than a CRT and produce little heat. Physical Aspects Take up about 40% less desk space. LCDs are thin and compact. Screen Shape Completely flat screen. Sharpness At the native resolution, the image is perfectly sharp. Adjustments are required at all other resolutions which can result in measurable degradation to the image. LCD Disadvantages Aspect Ratio The aspect ratio and resolution are fixed. Black-Level Not proficient at producing black and very dark grays. In a "standard" configuration, not appropriate for use in dimly lit and dark conditions. Contrast Lower contrast than CRTs due to a poor black-level. Color and Gray-Scale Accuracy Color saturation is reduced at low intensity levels due to a poor black-level. Images are satisfactory, but not accurate due to problems with black-level, gray-scale and Gamma. Cost Considerably more expensive purchase price than comparable CRTs . (Cheaper lifetime cost: lasts about 13,000 - 15,000 more hours than a typical CRT.) Gray-Scale Have an irregular intensity scale and typically produce fewer than 256 discrete intensity levels. For some LCDs portions of the gray-scale may be dithered. Motion Artifacts Slow response times and scan rate conversion result in severe motion artifacts and image degradation for moving or rapidly changing images. Resolution Works best at the native resolution. The native resolution can not be changed. All other resolutions require adjusting procedures which can cause considerable deterioration of the image. Viewing Angle Restricted viewing angles. Viewing angles affect the brightness, contrast and colors shown. Wide angles can lead to contrast and color reversal. White Saturation Saturation and compression can occur due to the bright-end of the intensity scale becoming overloaded. Contrast control must be carefully adjusted. Advantages of using LEDs > LEDs produce more light per watt than do incandescent bulbs; this is useful in battery powered or energy saving devices. > LEDs can emit light of an intended color without the use of color filters that traditional lighting methods require. This is more efficient and can lower initial costs. > The solid package of the LED can be designed to focus its light. Incandescent and fluorescent sources often require an external reflector to collect light and direct it in a usable manner. > When used in applications where dimming is required, LEDs do not change their color tint as the current passing through them is lowered, unlike incandescent lamps, which turn yellow. > LEDs are ideal for use in applications that are subject to frequent on-off cycling, unlike fluorescent lamps that burn out more quickly when cycled frequently, or HID lamps that require a long time before restarting. > LEDs, being solid state components, are difficult to damage with external shock. Fluorescent and incandescent bulbs are easily broken if subjected to external shock. > LEDs can have a relatively long useful life. Reports estimates 60,000 hours of useful life, though time to complete failure longer.2 Fluorescent tubes typically are rated at about 30,000 hours, HID and MH are rated anywhere between 10,000 and 24,000 hours and incandescent light bulbs at 1,000–2,000 hours. > LEDs mostly fail by dimming over time, rather than the abrupt burn-out of incandescent or HID bulbs.3 This provides extra safety for any area illuminated by LEDs. Even if the LEDs dim over time, they never fail completely like HID sources before needing to be replaced. LEDs need to be replaced only after they reach 30% lumen depreciation (17-20 years for quality LEDs). > LEDs light up very quickly. A typical red indicator LED will achieve full brightness in microseconds; Philips Lumileds technical datasheet DS23 for the Luxeon Star states "less than 100ns." LEDs used in communications devices can have even faster response times. > LEDs can be very small and are easily populated onto printed circuit boards. > LEDs do not contain mercury, unlike compact fluorescent lamps. Disadvantages of using LEDs > On an initial capital cost basis, LEDs are currently more expensive, measured in price per lumen, than more conventional lighting technologies. The additional expense partially stems from the relatively low lumen output, combined with the cost of the drive circuitry and power supplies needed. However, when considering the total cost of ownership (including energy and maintenance costs), LEDs far surpass other sources. In December 2007, scientists at Glasgow University claimed to have found a way to make Light Emitting Diodes brighter and use less power than energy efficient light bulbs currently on the market by imprinting holes into billions of LEDs in a new and cost effective method using a process known as nanoimprint lithography.4 Around the same time, in Montreal Canada, Lumec inc. developed an LED light engine that consumes 20% to 30% less energy than HPS (high pressure sodium) and 40% to 50% less than MH (metal halide) while delivering comparable photometric performance, if not better, than HID lights. > LED performance largely depends on the ambient temperature of the operating environment. Driving the LED hard in high ambient temperatures may result in overheating of the LED package, eventually leading to device failure. Adequate heat-sinking is required to maintain long life. This is especially important when considering automotive, outdoor, medical, and military applications where the device must operate over a large range of temperatures, and is required to have a low failure rate. The most heat resistant LEDs available commercially, such as those used by Lumec inc. In their light engine, the LifeLEDTMcan function at optimal efficiency from -40°C to +50°C(-40°F to 122°F) Q.3 Which among the following are the primary Producers ? 1) Plants 2) Lichens 3) Fungi 4) Cyanobacteria Codes: A) 1,2,3 B) 1,3,4 C) 1,2,4 D) Only 1 & 4 Ans. C Q.4 Project “Arrow” is related to the : A) Wing of Armed forces B) Standard of quality of garments C) Giving a new identity to post offices D) Welfare of old scheduled tribes Ans. C Q.5 Plants which are known as the Petro Crops, are rich in : 1) Carbohydrates 2) Proteins 3) Hydrocarbons 4) Lipids Codes: A) 1,2,3 B) 2 & 4 C) 2,3,4 D) 3 & 4 Ans. D Q.6 In context with the news there was a term “NETRA” What it is ? A) Device which allows army to undertake right reconnaissance B) Device which permits blind man to read C) Unmanned aerial vehicle which can travel upto 300 metres high D) None of the above Ans. C Q.7 In context with the news there was a term “Blue Chip”. What it means ? A) Shares giving high rate of return B) Shares guaranted by the governments C) Shares listed in the Stock Exchange D) None of the above Ans. A Q.8 Statements: 1) AIDS virus contains DNA, RNA & Protein 2) Biochip contains RNA & DNA Codes: A) Only 1 B) Only 2 C) Both are correct D) Both are incorrect Ans. D AIDS virus contains DNA & Protein Biochip contains RNA Q.9 In context with the news there was a term “Selecshaw” What it means ? A) It is a sole of footwear B) It is a Solar Rickshaw C) It is a Moon Buggy D) It is a Computer programme Ans. B Q.10 Which of the following is/are correct regarding biopiracy ? 1) They are protected by the law 2) These are employed by the corporations & governments Codes: A) Only 1 B) Only 2 C) Both are correct D) Both are incorrect Ans. C Q.11 Which of the following are the characteristics of the Monoclonal antibodies ? 1) These can be injected to kill or inhibit specific cells 2) These are more specific & reproducible 3) These can be used for immune suppression Codes : A) 1 & 3 B) 2 & 3 C) 1 & 2 D) 1,2,3 Ans. D Q.12 ELISA technique is used for the detection of : 1) Bacteria 2) Fungi 3) Virus Which among above is/are correct ? A) 1 & 3 B) Only 1 C) 2 & 3 D) 1,2,3 Ans. D ELISA is used for detection of Infectious diseases like T.B., AIDS Q.13 Which among the following are correct regarding AIDS; 1) It is contagious 2) It has been classified under the secondary immunodeficiency 3) It generally attacks helper T-cells Codes: A) 1 & 3 B) 2 & 3 C) 1 & 2 D) 1,2,3 Ans. D Q.14 Which of the following are the sexually transmitted diseases ? 1) Genital Herpes 2) Hepatitis B 3) AIDS Codes: A) Only 3 B) 2 & 3 C) Only 1 D) 1,2,3 Ans. D